Variable displacement recovery devices

ABSTRACT

This invention provides controlled buoyancy at depth displacement of water. The apparatus includes an expansible lift bag, a gas source, with a gas delivery device connecting the gas source with the lift bag. A valve controls the supply of gas from the source, while another valve vents gas from the lift bag. Both valves are controlled by ascent velocity sensing devices controlling the supply and vent valves in sequence either to regulate ascent velocity or to suspend a load at depth. An outer container is provided for packing all components and for attachment of loads.

2,635,574 4/l953 Sturteuant ..l l4/54 United States Patent 11513,659,299 Davidson et al. 1 May 2, 1972 s41 VARIABLE DISPLACEMENT3,372,996 3/1968 Barren et al ..114/53 RECOVERY DEVICES 3,471,87710/1969 Bayles ..9/8 [72] Inventors: r g"; n??? Cole PrimaryExaminer-Milton Buchler o o a Assistant Examiner-Gregory OConnor [73]Assignee: Proteus, Inc., Mountain Lakes, NJ. 221 Filed: Dec.29, 1969 5ABSTRACT This'invention provides controlled buoyancy at depth dis- [21]Appl' 888345 placement of water. The apparatus includes an expansiblelift 1 bag, a gas source, with a gas delivery device connecting the U.S.Cl- R, l gas ource the A valve controls the u ly of ga [51] 'f CI 1 B63:7/00 from the source, while another valve vents gas from the lift [58]Field of Search ..9/8 R, 9; l l4/54,53, 16.3 bagv Both valves arecontrolled by ascent velocity Sensing devices controlling the supply andvent valves in sequence [56] References cued either to regulate ascentvelocity or to suspend a load at depth. UNITED STATES PATENTS An outercontainer is provided for packing all components 7 and for attachment ofloads. 2,451,002 10/1948 Sturteuant.... ....l 14/54 8 Claims, 6 DrawingFigures PATENTEDMAY 2 I972 SHEET 10F 2 FIG. 3B.

INVENTORS WILLIAM M DAV HOWARD W. CO

FIG. 30.

This invention relates to an inflatable flotation device useful forlifting, transporting, suspending or recovering submerged loads, suchas, instruments, tools, markers, lights and other equipment.

The flotation device described herein comprises a cylindrical containerenclosing an inflatable lift bag, a chemical gas generator and controlsfor operation of the device. The lower end of the inflatable bag isfixed inside of the container to the outlet of the gas generator, whilethe upper end of the inflatable'bag is fixed to the inside of the uppercover, which may be a fixed float. Gas generating means, preferably madeup of a solid chemical compound reactive upon contact with water togenerate a gas, suchas hydrogen gas, is provided within the containeradjacent to the lower cover. The container is free flooding and when thegas generating means is activated to expose said chemical compound, suchas a hydride of a metal selected from the group consisting a lithium,sodium, calcium, potasssium and aluminum and mixtures thereof, tocontact with water, the resulting generated gas releases the top coverfrom the container and deploys the bag which is then inflated by the gasand thereby displaces water surrounding the inflatable bag soas to liftthe submerged'object to which the device is attached. 7

This invention further relates to floatation devices and elements andcompositions useful therefor, In accordance with one embodiment thisinvention relates to a light-weight, readily transportable flotationdevice useful for divers for attachment to a submerged load for lifting,transporting, suspending or recovering the same when the device isactuated. In accordance with another embodiment this invention isdirected to a method of inducing water to flow into and through thereaction zone of the generator for purposes of completing the reactionand to remove heat as well as reactants, such as the hydroxide of themetal fuel, on a continuous basis by thermo-syphon action.

' In accordance with anotherembodiment this invention is directed tochemical compositions capable of reacting upon contact with water,including sea water, to generate a gas, such as hydrogen-gas, and inaddition are capable of controlled reactivity such that the rate of gasgeneration can be controlled at-any desired rate including'stopping andrestarting the reaction.

In accordance with yet another embodiment this invention is directed toa method of stopping and starting the gas generator as a function of thevertical velocity of the elevator device.

In accordance with another embodiment this invention is directed to amethod of venting the inflatable bag as a function of the verticalvelocity of the elevator device. I I

In accordance with yet another embodiment this invention is directed toa method of controlling rate of ascent of the elevator device and load,suspending a load or cycling the load up and down by means of the saidvelocity controls, used individually or in combination. 1

In accordance with another embodiment this invention is directed towarda compact, light-weight, simple elevator device for lifting,transporting or suspending submerged loads where a compressed gas bottleand suitable regulator are incorporated in the container with theinflatable lift bag in substitution for the chemical gas generator.

' Flotation or recovery devices employed heretofore for liftingsubmerged loads have, for the most part, been ineffective or too heavy,cumbersome and complicated in operation or structure and expensive tomanufacture. Alternatively, the simple diver bag used for lifting byinflating with compressed air or exhaled breathing air is often unsafeto use because of the runaway ascent produced by gas expansion duringascent of the load. A heavy, bulky or cumbersome lift system isundesirable for diver use.

Accordingly, it is an object of this invention to provide a simple,effective, readily transportable lift device for elevating,transporting, suspending or recovering submerged loads. It is anotherobject of this invention to provide a light-weight,

substantially foolproof system and compositions usefulin associationtherewith for diver use in lifting, transporting,

v suspending or recovering submerged loads.

It is also an object of this invention to provide a means forcontrolling rate of ascent, suspending a load or cycling the load up anddown either by means of manual control or automatically by means ofvelocity controls.

In at least one embodiment of this invention at least one of theforegoing objects will be achieved.

How these and other objects of this invention are achieved will becomeapparent in the light of the accompanying disclosure and drawingswherein: I FIG. 1 illustrates schematically one use of the elevatordevice in accordance with this invention for supporting a tool at anunderwater work site.

FIG. 2 is an outline view of the elevator device showing the closed orpackaged configuration in the non-operating condition prior toactivation of the gas generator.

FIGS. 3, B, and C show three vertical cross-section views of theelevator device including details of the gas generator and controls 7FIG. 3D shows a plain view of a diaphragm in the velocity sensingcontrol. I

The elevator device in accordance with this invention is characterizedby certain features which make it useful for a wide variety ofapplications. For example, since the device is simple, compact andrelatively light-weight, it can be readily transported and delivered tothe worksite for use. Further, since the elevator device when submergedexhibits substantially neutral buoyancy it can be readily employed by adiver or sent to the bottom on a down-line for either standby use or forattachment to a load to be elevated. If desired, the buoyancy of theelevator device, by suitableadjustment, such as by changing the amountof buoyant materials therein, can be modified to exhibit a positive or anegative buoyancy when submerged. In addition, the elevator device inaccordance with one embodiment of this invention can be used to lift anyload, up to its full rated lift capacity, without exceeding the desiredpreset rate of ascent.

' FIG. 1 illustrates an operation wherein an elevator device inaccordance with this invention is attached to a tool, such as anunderwater wrench, and used for the purpose of suspending the tool sothat the diver can concentrate on operating the tool rather than onsupporting the weight of the tool.

FIG. 2 illustrates a fixed flotation collar at the 'top of the deviceand a pull ring extending from the lower extremity of the container thatmay be used for activating the gas generator.

FIG. 3 illustrates the detail componentscontained within one embodimentof this invention; the elevator device, generally referred to by numeral1, comprises a top cover or fixed float collar 2, a cylindricalcontainer 3, a bottom cover and load support bracket 4, an inflatablelift bag 5, a chemical gas generator 6, a velocity control 7 for the gasgenerator, and a velocity control 8 for venting inflatable lift bag 5.Fuel cartridge 9 contains a chemical compound, such as hydride fuel,which upon contact with water generates a gas, in this case hydrogengas. Hydraulic line 10, which is connected to fuel cartridge 9, is usedto apply a small differential pressure inside fuel cartridge 9 for thepurpose of removing cover 11 to expose the fuel and thereby activate thegas generator. Hydraulic line 10 may be used as an alternate to themanual pull ring method illustrated in FIG. 1. When cover 11 is removed,fuel from inside of cartridge 9 is free to fall onto open-wire grate 12where it can react with water that fills generator 6. The generator gasrises and passes around fuel cartridge 9 and into the open bottom end oflift bag 5 through port 13. Reaction of the fuel with water generatesheat in addition to gas. Most of the heat is absorbed directly by thewater and is conducted thereby to sleeve 14 made of a material havinghigh heat conductivity, such as aluminum. Sleeve 14 transfers heat tothe water occupying the annular space between sleeve 14 and containerbody 3. This annular space, referred to herein as a chimney is connectedto the reaction zone of gas generator 6 by means of radial holes 28 atthe bottom and is vented to ambient water pressure by another set ofradial holes 29 at the top through container body 3. Bottom cover 4 hasholes located near its center that connect the reaction zone of gasgenerator 6 to ambient water pressure at the bottom- In operation, uponsubmergence of elevator device 1, all internal volumes flood freely withwater. Activation is initiated by command, either remotely or directlyby manual means, such as by applying a small positive pressuredifferential, for example by mouth or with a squeeze bulb, to line 10.Removal of lid 11 and initiation of the gasreaction is therebyaccomplished as described above. The gas, being light, displaces waterfrom the reaction zone of gas generator 6 working against a head ofwater (approx. 10-12 inches of water) produced by the chimney betweenits upper and lower vent holes; The gas pressure developed by this headis sufficient to release cover 2 from its attaching clamp or otherretainerand to deploy the inflatable lift bag 5 from container body 3.Gas then continues to enter lift bag 5 through port 13. Port 13 containsan orifice 27 that controls .the rate at which lift bag 5 is inflated.Port 13 also functions as a gas/water separator that.

allows water to-flow by force of gravity back to the reaction zone ofgas generator 6 through tube 15. When lift bag 5 has inflated fully, theback pressure will expel water from the reaction zone of generator 6 tobelow the level of grate 12,.thereby stopping the gas generation. Thiscondition will prevail as long as the pressure head of the chimney isbalanced against the gas pressure inside the reaction zone of generator6. While generator 6 is operating, the thermo-syphon action of thechimneney will continually pump fresh water into the reaction zone ofgenerator 6 and purge reactants (hydroxide) up through the chimney andout through the vent holes at the top.

The foregoing discussion illustrates how the elevator device regulatestherate of gas generation automatically without the need for valves orother control devices. FIG. 3B illustrates one method of using velocitycontrols to relates the rate of gas generation to the rate at which theelevator device ascends. Velocity control 7 consists of diaphragm 16,located under port 13, and pitot tube 17, attached to the outside ofcontainer body 3. Gas from generator 6 passes through the cavity abovediaphragm 16 before entering outlet port 13. The cavity under diaphragm16 is connected to external velocity pressure at an elevationsubstantially the same as that of grate 12 through tube" 17. Tube 17 isessentially a pitot tube that balances velocity pressure external to theelevator device against gas pressure inside lift bag 5. Vertical motionof the lift device thus causes pressure below the, diaphragm to increaseand forces diaphragm 16 to move upward and close the inlet to port 13,thereby preventing gas from entering lift bag 5 and increasing the backpressure in the reaction zone of generator 6. The entrapped gas willexpel water from the reaction zone until the water level has droppedbelow grate 12 at which time the generator will crease to generate gas.

Stopping the supply of gas to lift bag 5, by itself, will not stop thevertical ascent of the elevator device because the gas already insidethe inflatable lift bag will continue to expand with decreasing depthand hydrostatic pressure. In order to control or to stop the verticalascent, it is, therefore, necessary also to vent gas from the inflatablebag 5. FIG. 3C illustrates a velocity sensitive vent control 8, locatedat the top of lift bag 5 for this purpose. Vent control 8 consists ofdiaphragm 18, seal 19, push rod 20', plate 21, spring 22 and nut 23.Flexible diaphragm 18 operates the poppet type vent valve seal 19 in thetop of lift bag 5 by moving pushrod 20. The cavity above diaphragm 18senses velocity head pressure components through holes in plate 21. Thecavity below diaphragm l8 senses hydrostatic pressure outside theelevator device through hole 26 in the periphery of float collar 2.Spring 22, with compression adjusted by means of nut 23, determines thepressure at which the velocity head will open the vent valve.

Vertical motion of elevator device 1 increases the pressure abovediaphragm 18 until the force exerted on the diaphragm is equal to thepreset load on spring 22. Diaphragm 18 then opens valve seal 19 bypushing on rod 20. Diaphragm 18 displacement and valve opening areproportional and gas vents accordingly from inflatable lift bag 5through the static pressure vents 26 in float collar 2. Venting of gasfrom lift bag 5 decreases the displacement of elevator device 1 andthereby reduces its vertical velocity until the velocity head isovercome by the force on spring 22 and-vent valve seal 19 closes. Thus,the ascent rate of elevator device 1 can be predetermined by propercalibration and setting of velocity vent valve 8.

The use of two independent velocity controls, providing for cut-ofl ofthe gas generator at an ascent velocity less than the velocity requiredfor venting the lift bag, is a feature that enables the use of elevatordevice 1 for the lateral transfer of undersea equipment from onelocation to another. Such elevator operation can be accomplished eitherby manual or automatic control of the valves. Furthermore, equipmentloads can be suspended at any desired depth, such as for example, thesuspension of cameras or flood lights above a work site. Descent of theelevator device will cause the gas generator to restart, while verticalmotion will adjust lift by venting lift bag 5. Another feature providedby the velocity controlsis that the elevator device will have the samepreset rate of ascent for a light load as for a load equal to full liftcapacity. A light load will be elevated when inflatable lift bag 5 isonly partially inflated; velocity controls 7 an 8 will act in sequenceto control rate of ascent to the preset value. Lifting forces created bythe partially inflated lift bag 5 are transmitted to container body 3and thereby to load support cover 4 through a scrim or sleeve I 24 thatsurrounds lift bag 5 and is attached between the top of container body 3and the top of lift bag 5.

Referring now to FIG. 3B, the addition of plate 25 restricts the passageof water through bottom cover 4 to the centerline of elevator device 1.This feature permits the tilt angle for proper operation of the deviceto. be markedly increased without exposing the gas to ventsin bottomcover 4. Further, it is obvious that reaction pressure can be controlledby adjustment of the pressure head,.such as by raising or lowering theposition of grate 12 or by adjusting the location of upper dischargeholes in container body 3 at the top of the chimney."

Elevator device 1 in accordance with this invention has the ability tooperate at substantially any depth and/or to lift any size load withsubstantially the same basic structure. Further, the relative volumesoccupied by lift bag and fuel can be varied to suit the depth, load andduration of operation. Reuse of elevator device 1 is accomplished simplyby replacement of fuel cartridge 9 and repacking of inflatable lift bag5. i

As will be apparent to those skilled in the art in the light of theforegoing disclosure, many modifications, alterations and substitutionsare possible in the practice of this invention without departing fromthe spirit or scope thereof.

We claim:

1. An underwater lift device consisting of: (a) a gas container, such asan expansible lift bag, to provide buoyancy by displacement of water;(b) a gas source; (c) gas delivery means communicating said gas sourcewith said gas container; (d) actuating means for said gas source toprovide gas at the required pressure depth for said gas container; (e) agas supply control valve for said gas source, responsive to containedgas pressure balanced against hydrodynamic pressure as determined byrate of ascent; (f) a gas vent valve affixed to said gas containerresponsive to contained gas pressure balanced against hydrodynamicpressure as determined by rate of ascent; (g) an outer container tohouse and protect the apparatus packaged within said outer container;and a (h) means for attachment of a load to said outer container.

2. An underwater lift device in accordance with claim 1 wherein said gassource is a chemical gas generator consisting of a chemical compound orfuel, such as an hydride of a metal selected from a group consisting oflithium, sodium, calcium, potassium, aluminum and mixtures thereof, saidfuel being packaged in a fuel cartridge with a sealed closure, whichwhen opened by hydraulic means deploys said fuel into water surroundingsaid fuel cartridge whereupon said fuel reacts with the water togenerate relatively pure hydrogen gas, said reaction being confined by awire grate located under said fuel cartridge and by cylindrical metalsleeve surrounding said fuel cartridge, wherein the metal sleeve servesto transfer heat from the chemical reaction and by thermo-syphon actiondraw fresh water into the generator as well as to'purge the generator ofreacted materials, such as hydroxides of the metal.

3. An underwater lift device in accordance with claim 2 wherein thereaction rate and reaction pressure within said gas generator arecontrolled by gas pressure differential (relative to hydrostaticpressure) developed inside of said gas container, which pressuredifferential is balanced by the pressure head established by saidcylindrical metal sleeve between radial holes located near the upper andlower extremities of said sleeve, the resultant pressure beingsufficient to expel water from inside said sleeve to a level below saidwire grate, thereby slowing or stopping gas generation until pressurechanges permit water to reenter said sleeve.

4. An underwater lift device in accordance with claim 2 wherein saidfuel cartridge may be opened, to expose said fuel contents to water,thereby activating said gas generator, by means of an hydraulic lineconnected to said fuel cartridge through which water is injected intosaid sealed cartridge, either by means of hydrostatic pressure or anapplied differential pressure, to react with said fuel and to break andremove said sealed closure by means of gas pressure developed inside ofsaid fuel cartridge.

5. An underwater lift device in accordance with claim 1 wherein the gassupply control valve is a pressure-balanced valve, such as a diaphragmvalve, sensing hydrodynamic pressure on one side, as for example bymeans of a pitot tube with opening oriented toward the direction oftravel during ascent of the device, and gas supply pressure on theopposing side of the diaphragm, said valve operating to close said gasdelivery means communicating said gas source with said expansible liftbag whenever ascent rate exceeds a prescribed velocity and the resultanthydrodynamic pressure exceeds gas supply pressure.

6. An underwater lift device in accordance with claim 5 wherein the gasvent valve affixed to said gas container is a pressure-balanced valve,such as a diaphragm valve with spring loaded adjustment means, sensinghydrodynamic pressure on one side, such as by means of aperturesoriented toward the direction of travel during ascent, and contained gas1 pressure on the opposing side of the diaphragm, said valve operatingto vent contained gas from said gas container whenever assent rateexceeds a preset velocity as determined by spring bias holding saidvalve in the normally closed position, and resultant hydrodynamicpressure exceeds gas pressure inside said gas container in combinationin said lift device in a sequential manner, first to close said gasdelivery means thereby isolating said gas container from said gas supplyand, second, to vent gas from said gas container until the desiredvertical ascent velocity has been attained, including the suspension ofloads at some predetermined depth.

7. An underwater lift device in accordance with claim 1 wherein the gasvent valve afiixed to said gas container is a pressure-balanced valve,such as a diaphragm valve with spring-loading adjustment means, sensinghydrodynamic pressure on one side, such as by means of aperturesoriented toward the direction of travel during ascent, and contained gaspressure on the opposing side of the diaphragm, said valve operating tovent contained gas from said gas container whenever ascent rate exceedsa preset velocity, as determined by spring bias holding said valve inthe normally closed position, and resultant hydrodynamic pressureexceeds gas pressure inside said gas container. I

8. An underwater hft device 1n accordance with claim 1 wherein the gascontainer consists of an expansible lift bag employing an inner bladder,constructed of thin, flexible plastic, rubber or rubberized materialhaving low permeability to hydrogen gas, an outer sleeve, constructed offlexible but relatively inelastic material, such as vinyl coated Nylonreinforced fabrics, wherein the outer sleeve functions to protect andcontain the inner bladder, as well as to support lifting loads, whilethe inner bladder is free to conform irrespective of load and amount ofinflation, water being free to circulate between said sleeve and saidbladder.

1. An underwater lift device consisting of: (a) a gas container, such asan expansible lift bag, to provide buoyancy by displacement of water;(b) a gas source; (c) gas delivery means communicating said gas sourcewith said gas container; (d) actuating means for said gas source toprovide gas at the required pressure depth for said gas container; (e) agas supply control valve for said gas source, responsive to containedgas pressure balanced against hydrodynamic pressure as determined byrate of ascent; (f) a gas vent valve affixed to said gas containerresponsive to contained gas pressure balanced against hydrodynamicpressure as determined by rate of ascent; (g) an outer container tohouse and protect the apparatus packaged within said outer container;and a (h) means for attachment of a load to said outer container.
 2. Anunderwater lift device in accordance with claim 1 wherein said gassource is a chemical gas generator consisting of a chemical compound orfuel, such as an hydride of a metal selected from a group consisting oflithium, sodium, calcium, potassium, aluminum and mixtures thereof, saidfuel being packaged in a fuel cartridge with a sealed closure, whichwhen opened by hydraulic means deploys said fuel into water surroundingsaid fuel cartridge whereupon said fuel reacts with the water togenerate relatively pure hydrogen gas, said reaction being confined by awire grate located under said fuel cartridge and by cylindrical metalsleeve surrounding said fuel cartridge, wherein the metal sleeve servesto transfer heat from the chemical reaction and by thermo-syphon actiondraw fresh water into the generator as well as to purge the generator ofreacted materials, such as hydroxides of the metal.
 3. An underwaterlift device in accordance with claim 2 wherein the reaction rate andreaction pressure within said gas generator are controlled by gaspressure differential (relative to hydrostatic pressure) developedinside of said gas container, which pressure differential is balanced bythe ''''pressure head'''' established by said cylindrical metal sleevebetween radial holes located near the upper and lower extremities ofsaid sleeve, the resultant pressure being sufficient to expel water frominside said sleeve to a level below said wire grate, thereby slowing orstopping gas generation until pressure changes permit water to reentersaid sleeve.
 4. An underwater lift device in accordance with claim 2wherein said fuel cartridge may be opened, to expose said fuel contentsto water, thereby activating said gas generator, by means of anhydraulic line connected to said fuel cartridge through which water isinjected into said sealed cartridge, either by means of hydrostaticpressure or an applied differential pressure, to react with said fueland to break and remove said sealed closure by means of gas pressuredeveloped inside of said Fuel cartridge.
 5. An underwater lift device inaccordance with claim 1 wherein the gas supply control valve is apressure-balanced valve, such as a diaphragm valve, sensing hydrodynamicpressure on one side, as for example by means of a pitot tube withopening oriented toward the direction of travel during ascent of thedevice, and gas supply pressure on the opposing side of the diaphragm,said valve operating to close said gas delivery means communicating saidgas source with said expansible lift bag whenever ascent rate exceeds aprescribed velocity and the resultant hydrodynamic pressure exceeds gassupply pressure.
 6. An underwater lift device in accordance with claim 5wherein the gas vent valve affixed to said gas container is apressure-balanced valve, such as a diaphragm valve with spring loadedadjustment means, sensing hydrodynamic pressure on one side, such as bymeans of apertures oriented toward the direction of travel duringascent, and contained gas pressure on the opposing side of thediaphragm, said valve operating to vent contained gas from said gascontainer whenever assent rate exceeds a preset velocity as determinedby spring bias holding said valve in the normally closed position, andresultant hydrodynamic pressure exceeds gas pressure inside said gascontainer in combination in said lift device in a sequential manner,first to close said gas delivery means thereby isolating said gascontainer from said gas supply and, second, to vent gas from said gascontainer until the desired vertical ascent velocity has been attained,including the suspension of loads at some predetermined depth.
 7. Anunderwater lift device in accordance with claim 1 wherein the gas ventvalve affixed to said gas container is a pressure-balanced valve, suchas a diaphragm valve with spring-loading adjustment means, sensinghydrodynamic pressure on one side, such as by means of aperturesoriented toward the direction of travel during ascent, and contained gaspressure on the opposing side of the diaphragm, said valve operating tovent contained gas from said gas container whenever ascent rate exceedsa preset velocity, as determined by spring bias holding said valve inthe normally closed position, and resultant hydrodynamic pressureexceeds gas pressure inside said gas container.
 8. An underwater liftdevice in accordance with claim 1 wherein the gas container consists ofan expansible lift bag employing an inner bladder, constructed of thin,flexible plastic, rubber or rubberized material having low permeabilityto hydrogen gas, an outer sleeve, constructed of flexible but relativelyinelastic material, such as vinyl coated Nylon reinforced fabrics,wherein the outer sleeve functions to protect and contain the innerbladder, as well as to support lifting loads, while the inner bladder isfree to conform irrespective of load and amount of inflation, waterbeing free to circulate between said sleeve and said bladder.